Pain is one of the basic clinical symptoms. There is a worldwide need for effective therapies for pain. The urgent need for action for the treatment of chronic and non-chronic pain in a targeted manner which is fair to the patient, which is to be understood as meaning the successful and satisfactory treatment of pain for the patient, is documented in the large number of scientific works which have recently appeared in the field of applied analgesics or the fundamental research into nociception. For example, phencyclidine derivatives having analgesic activity are known from J. Med. Chem. 1981, 24, 496–499 and Arzneim.-Forsch./Drug Res. 44 (II), No. 10 (1994), 1141–1144.
Conventional opioids, such as, for example, morphine, are effective in the therapy of severe to very severe pain. However, they have, inter alia, respiratory depression, vomiting, sedation, constipation and the development of tolerance as undesirable side-effects. In addition, they are less effective in the case of neuropathic or incidental pain, as frequently occurs in tumor patients in particular.
Tramadol hydrochloride—(1RS,2RS)-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)-cyclohexanol—occupies a special position among the centrally acting analgesics, because that active ingredient brings about pronounced inhibition of pain without the side-effects known for opioids (J. Pharmacol. Exptl. Ther. 267, 33 (1993)).